Shaped inlets in a vaporizer

ABSTRACT

Reductions in flow resistance, associated with the results of a turbulent airflow in the atomization chamber, are provided through the use of at least one of air inlets and pre-wick airflow passages that make use of a curved sidewall connecting an input face larger than an output face. In some embodiments, a hyperboloid shaped inlet is used to reduce the turbulence associated with forcing an airflow around sharp corners. These shaped inlets and shaped pre-wick air flow passages can be used together or independently.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the first application for the instant invention.

TECHNICAL FIELD

This application relates generally to a design for inlets to a container, and more particularly to a pod having inlets designed for the reduction in flow resistance for use in conjunction with an electronic cigarette or vaporizer.

BACKGROUND

Electronic cigarettes and vaporizers are well regarded tools in smoking cessation. In some instances, these devices are also referred to as an electronic nicotine delivery system (ENDS). A nicotine based liquid solution, commonly referred to as e-liquid, often paired with a flavoring, is atomized in the ENDS for inhalation by a user. In some embodiments, e-liquid is stored in a cartridge or pod, which is a removable assembly having a reservoir from which the e-liquid is drawn towards a heating element by capillary action through a wick. In many such ENDS, the pod is removable, disposable, and is sold pre-filled.

In some ENDS, a refillable tank is provided, and a user can purchase a vaporizable solution with which to fill the tank. This refillable tank is often not removable, and is not intended for replacement. A fillable tank allows the user to control the fill level as desired. Disposable pods are typically designed to carry a fixed amount of vaporizable liquid, and are intended for disposal after consumption of the e-liquid. The ENDS cartridges, unlike the aforementioned tanks, are not typically designed to be refilled. Each cartridge stores a predefined quantity of e-liquid, often in the range of 0.5 to 3 ml. In ENDS systems, the e-liquid is typically composed of a combination of any of vegetable glycerine, propylene glycol, nicotine and flavorings. In systems designed for the delivery of other compounds, different compositions may be used.

In the manufacturing of the disposable cartridge, different techniques are used for different cartridge designs. Typically, the cartridge has a wick that allows e-liquid to be drawn from the e-liquid reservoir to an atomization chamber. In the atomization chamber, a heating element in communication with the wick is heated to encourage aerosolization of the e-liquid. The aerosolized e-liquid can be drawn through a defined air flow passage towards a user's mouth.

FIGS. 1A, 1B and 1C provide front, side and bottom views of an exemplary pod 50. Pod 50 is composed of a reservoir 52 having an air flow passage 54, and an end cap assembly 56 that is used to seal an open end of the reservoir 52. End cap assembly has wick feed lines 58 which allow e-liquid stored in reservoir 52 to be provided to a wick (not shown in FIG. 1). To ensure that e-liquid stored in reservoir 52 stays in the reservoir and does not seep or leak out, and to ensure that end cap assembly 56 remains in place after assembly, seals 60 can be used to ensure a more secure seating of the end cap assembly 56 in the reservoir 52. In the illustrated embodiment, seals 60 may be implemented through the use of o-rings.

As noted above, pod 50 includes a wick that is heated to atomize the e-liquid. To provide power to the wick heater, electrical contacts 62 are placed at the bottom of the pod 50. In the illustrated embodiment, the electrical contacts 62 are illustrated as circular. The particular shape of the electrical contacts 62 should be understood to not necessarily germane to the function of the pod 50.

Because an ENDS device is intended to allow a user to draw or inhale as part of the nicotine delivery path, a pre-wick airflow passage 64 having a plurality of air inlets 72 is provided on the bottom of pod 50. As will be seen in other figures, pre-wick air flow passage 64 is a recess within end cap assembly 56. The overall air flow path extends through an atomization chamber and then through post wick air flow passage 54.

FIG. 2 illustrates a cross section taken along line A in FIG. 1B. This cross section of the device is shown with a complete (non-sectioned) wick 66 and heater 68. End cap assembly 56 resiliently mounts to an end of air flow passage 54 in a manner that allows pre-wick airflow passage 64 to form a complete air path through pod 50. This connection allows airflow from pre-wick airflow passage 64 to pass through air inlets 72 and to connect to the post air flow path through passage 54 through atomization chamber 70. Within atomization chamber 70 is both wick 66 and heater 68. When power is applied to contacts 62, the temperature of the heater increases and allows for the volatilization of e-liquid that is drawn across wick 66.

Typically the heater 68 reaches temperatures well in excess of the vaporization temperature of the e-liquid. This allows for the rapid creation of a vapor bubble next to the heater 68. As power continues to be applied the vapor bubble increases in size, and reduces the thickness of the bubble wall. At the point at which the vapor pressure exceeds the surface tension the bubble will burst and release a mix of the vapor and the e-liquid that formed the wall of the bubble. The e-liquid is released in the form of aerosolized particles and droplets of varying sizes. These particles are drawn into the air flow and into post wick air flow passage 54 and towards the user.

FIGS. 3A and 3B illustrate a pod 74 having a different construction than pod 50. Those skilled in the art will appreciate that the functioning of the pod 74 is quite similar despite the different construction. Pod 74 has a reservoir 76, with a post-wick air flow passage 78, and an end cap assembly 80. End cap 80 includes electrical contacts 82, a pre-wick air flow passage 84, and an atomization chamber 86. Pre-wick air flow passage connects to the atomization chamber 86 by way of inlets 88. Within atomization chamber 86 is wick 90. Heater 92 is connected to electrical contacts 82, and when provided power by a vaping device, heater 92 will be raised to a temperature that causes vaporization of the e-liquid adjacent to heater 92. This vaporization will create a bubble that will expand under the vapor pressure until the surface tension of the e-liquid is no longer strong enough to hold the bubble together. At this point the bubble will rupture and vapor and droplets of varying sizes will be entrained within an airflow moving from prew-wick airflow passage 84, through atomization chamber 86 and into post-wick airflow passage 78. The e-liquid adjacent to the heater 92 is drawn across wick 90, typically through a capillary flow, and is fed from reservoir 102 into the wick through wick feed lines 94.

In both illustrated embodiments, the inlets that allow air to flow from outside the pod towards the inside of the pod are shown as effectively cylindrical in shape. This use of a cylindrical shape is an artifact of the molding processes employed in the manufacture of the pod. Pods are typically created through the use of injection molding, and attempts are made to keep the cost of the device as low as possible. Cylinders are typically an easy shape to mold, and are thus preferred in current pod designs.

For the purposes of discussing an airflow passing through the pod, having inlets as large as possible is beneficial for the purposes of reducing a flow resistance in the airflow path. From the opposite perspective, the inlets are often restricted in size to create a seal below the wick. As e-liquid condenses in the post wick air flow passage, it will form droplets on the interior walls of the passage which can fall to the bottom of the pod. If the inlets are large enough this will result in the condensed e-liquid leaking out of the pod. This is considered to be a bad user experience, and leaking e-liquid can foul the electrical connections. If inlets are sufficiently narrow, the surface tension of the e-liquid will prevent the e-liquid from leaking from the pod.

There is a desire to allow for the greatest airflow possible through the pod, as it provides the user with an easier draw. The ease with which a user has to draw on a device to activate the heating of the heater is a characteristic of the device, and many users prefer a draw without great resistance. Even after activation, a continued draw with low resistance allows the user to vape without a perceived great exertion which is considered to be a factor in a good user experience.

Thus, it should be understood that larger overall inlet size is preferred from an airflow experience perspective, while limiting any individual inlet size to ensure that a capillary seal effect is maintained to avoid leakage. To work within these optimization constraints, some pod designs increase the number of inlets, to allow for a maximization of airflow, while preserving the capillary sealing effect provided by small inlets.

One issue that arises with the increased number of inlets is that there is still a high flow resistance. Even with the increased number of inlets, flow resistance is still higher than many users would prefer. A fluid dynamics based analysis of the situation provides an indication of one of the sources of the flow resistance, which is that smaller cylindrical inlets create flow resistance because they require air in a confined area, such as a pre-wick air flow passage) to follow an air flow path that has tight curves. Airflow paths with tight curves are known to induce turbulence, which has the effect of increasing the flow resistance.

Another issue that has arisen in vaporizer design is the issue of backflow. When a user stops drawing on the device, the airflow temporarily reverses direction. This reversal may be short lived, but it can cause e-liquid and e-liquid laden air to be pushed out of the atomization chamber, and into the pre-wick airflow path. This may give the appearance of the pod leaking. The complete set of exact causes of backflow are not completely known, however it is believed that backflow may be associated with the design of the airflow path. Backflow can result in negative effects, including pulling e-liquid through the inlets, and pulling e-liquid laden air backwards through the pod.

It would therefore be beneficial to have a mechanism to further mitigate at least one of backflow and flow resistance to the airflow through the pod.

SUMMARY

It is an object of the aspects of the present invention to obviate or mitigate the problems of the above-discussed prior art.

To address issues with at least one of back flow and flow resistance, a modification to the design of elements in the air flow path can be provided. By designing one or both of the pre-wick air flow passage and the inlets between the pre-wick airflow passage and the atomization chamber to have a more gradual transition between portions of the airflow path, a reduction in flow resistance may be achieved. This may also alleviate some of the issues associated with backflow.

In a first aspect of the present invention, there is provided a pod for storing an atomizable liquid, and for use in an electronic vaporizer. The pod comprises an atomization chamber and a pre-wick airflow passage. The atomization chamber houses both a wick and a heater, and may optionally connect to a post-wick airflow passage. The pre-wick airflow passage connects to the atomization chamber by way of an inlet. The inlet has both input and output faces that are connected by a sidewall. The input face is larger than the output face.

In some embodiments, the atomizable liquid is an e-liquid that is comprised of at least one of propylene glycol, vegetable glycerin, nicotine and a flavoring.

In embodiments with a post-wick air flow passage, there is an airflow passage associated with the pod that is defined by the serial connection of pre-wick airflow passage, the inlet, the atomization chamber and the post-wick airflow passage connected in series.

In some embodiments, the sidewall of the inlet is curved and may optionally be defined by a segment of an ellipse. In some embodiments, the output face of the inlet is sized in accordance with characteristics of the atomizable liquid to prevent e-liquid from passing from the output face of the inlet to the input face of the inlet.

In some embodiments, the pre-wick airflow passage has an input face and an output face, smaller than the input face, connected by a sidewall. The sidewall may be shaped in accordance with a segment of an ellipse in some embodiments. In some embodiments there is a second pre-wick airflow passage with an input face and an output face connected by a sidewall, where the output face is smaller than the input face and connects the second pre-wick airflow passage to the atomization chamber through an inlet. In some embodiments, the inlet of the second pre-wick air flow passage has an input face larger than an output face connected by a curved sidewall.

In some embodiments, the atomization chamber and pre-wick airflow passage are connected by a plurality of inlets.

In a second aspect of the present invention, there is provided a pod for storing an atomizable liquid, for use in an electronic vaporizer. The pod comprises an atomization chamber and a pre-wick airflow passage. The atomization chamber houses a wick and heater. The pre-wick airflow passage is connected to the atomization chamber by an inlet, and it has an input face larger than the output face and connected by a sidewall.

In some embodiments, the atomizable liquid is an e-liquid comprising at least one of propylene glycol, vegetable glycerin, nicotine and a flavoring. In other embodiments, the atomization chamber is further connected to a post wick airflow passage. In further embodiments, the sidewall of the pre-wick airflow passage is curved and may be shaped in accordance with a segment of an ellipse.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described in further detail by way of example only with reference to the accompanying figure in which:

FIG. 1A is a front view of a pod, with a sectioned top cap;

FIG. 1B is a side view of the pod of FIG. 1A, having a sectioned top cap;

FIG. 1C is a bottom view of of the pod of FIG. 1A;

FIG. 2 is a cross section of the pod of FIG. 1B along section line A;

FIG. 3A is a cross section view of an alternate pod design;

FIG. 3B is a bottom view of the pod of FIG. 3A;

FIG. 4 is a cross section view of a pre-wick airflow passage and inlets of a pod according to an embodiment of the present invention;

FIG. 5 is a cross section view of a pod according to an embodiment of the present invention; and

FIG. 6 is a cross section view of a pod according to an embodiment of the present invention.

In the above described figures like elements have been described with like numbers where possible.

DETAILED DESCRIPTION

In the instant description, and in the accompanying figures, reference to dimensions may be made. These dimensions are provided for the enablement of a single embodiment and should not be considered to be limiting or essential. Disclosure of numerical range should be understood to not be a reference to an absolute value unless otherwise indicated. Use of the terms about or substantively with regard to a number should be understood to be indicative of an acceptable variation of up to ±10% unless otherwise noted.

To mitigate flow resistance issues associated with turbulence caused by conventional pod inlet design, curved inlets, and in some embodiments, a curved pre-wick airflow passage, are employed. Each inlet has two faces, an input face for allowing outside air to be drawn in (the intake face of an inlet), and an output face through which air flows into the pod (an outlet face of the inlet). By having an outlet face sufficiently small, the capillary sealing effect can be preserved, while an intake face larger than the outlet face allows for an inlet design that mitigates turbulence, and thus provides a lower flow resistance.

Turbulence in the intake of air can have a number of effects, none of which are desirable in the design of a pod. Turbulence may result in a “pulsing” of the airflow where the amount of air that passes through the inlets varies in volume over time. This variation in the volume of the airflow can be perceived by the user as a poor experience. Where the prior art solution was to create larger individual inlets, there is a limit to which this solution can be implemented without encountering disadvantageous side effects.

FIG. 4 illustrates, in cross section, a portion of pod 100. End cap 106 provides a structure that defines pre-wick air flow passage 112, inlets 114, and atomization chamber 116. Within atomization chamber 116 is wick 118 and heater 120. These elements will be illustrated in the context of a complete pod 100 in subsequent figures. It should also be understood that as illustrated in FIG. 4, none of these elements are shown to scale, nor are the sizes of the elements proportional to other elements. Elements are shown here for the sake of explanation and discussion. A more accurate representation of the scale of the elements will be shown in subsequent figures.

As illustrated in FIG. 4, pre-wick air flow passage 112 is shown with curved sidewalls, allowing passage 112 to have differently sized input face 112 i and output face 112 o. By having differently sized input 112 i and output 112 o faces, inlet 112 allows for a smoother airflow than would be permitted by having straight walls with hard corners as would be found in an inlet with equally sized input and output faces.

At the outlet face 112 o of pre-wick airflow passage 112, are inlets 114 through which the airflow passes to enter atomization chamber 116. Inlets 114 have an input face 114 i and an output face 114 o that are differently sized. The output face 114 o is smaller than the input face 114 i, and in some embodiments is sized to ensure that e-liquid resting atop the inlet 114 will be prevented from leaking out of pod 110 through a capillary seal. Thus, in some embodiments the size of output face 114 o is determined in accordance with characteristics (such as viscosity and surface tension) of the e-liquid stored in pod 100. Input face 114 i is larger than output face 114 o, and the sidewalls connecting them may be curved as shown in FIG. 4. This curve, much like the curved sidewalls of pre-wick air flow passage 112, avoid forcing airflow 124 into sharp angles. This curve allows for a softer change in airflow direction, which mitigates the creation of turbulence, and has the effect of reducing the flow resistance experienced by airflow 124.

Inlets 114 can be placed to open into atomization chamber 116 so that airflow 124 is directed towards wick 118. In some embodiments, airflow features may be introduced between wick 118 and inlet 114, as is taught in co-pending U.S. patent application Ser. No. 17/212,211 filed Mar. 25, 2021 and entitled “Pod with Airflow Features in a Pre-Wick Airflow Passage”.

By mitigating the effects of turbulence through creating a smoother airflow path, inlets 114 allow for a more consistent and predictable airflow into atomization chamber 116. This allows the airflow through atomization chamber 116, and onto wick 118 to be more predictable and reliable. In turn, this can allow for additional airflow features to be modelled and employed.

FIG. 5 illustrates the shaped inlet and pre-wick airflow passage introduced in FIG. 4, in the broader context of pod 100. Pod 100 comprises a reservoir 102, having a post wick air flow passage 104, an end cap 106 that engages with reservoir 102 to seal its open end. End cap 106 is retained in reservoir 102 through a friction fit and sealing engagement using resilient top cap 122 to create a seal. End cap 106 defines wick feed lines 108, through which e-liquid stored in reservoir 102 is fed to wick 118. This allows wick 118, within atomization chamber 116, to draw e-liquid towards heater 120. Within end cap 106 are electrical contacts 110 that allow pod 100 to electrically engage with a vaporizer which can, when activated, provide power to pod 100 through electrical contacts 110. Electrical contacts 110 are connected to heater 120, so that the application of power to pod 100 causes the heating and vaporization of e-liquid as described above.

Pre-wick air flow passage 112, allows air from outside the pod 100 to be drawn toward inlets 114 and then into atomization chamber 116, past heater 120 and wick 118 and out through post-wick air flow passage 104.

The airflow, drawn into pod 100, will typically correspond with activation of the vaporizing device, and thus the application of power to heater 120. By having pre-wick air flow passage 112 with a larger input face than output face, and with curved sidewalls, the airflow is allowed a gently curved passage towards inlets 114. This allows for a reduction in the turbulence that would be caused by a pre-wick airflow passage having sharp angles.

Similarly, if inlets 114 are shaped to allow for a smoother airflow, the effect provided by the shaped pre-wick air flow passage 112 is not reduced, and the airflow can be smoothly and predictably delivered towards wick 118 and heater 120. A more consistent airflow than would be provided by the inlets and pre-wick passage of the prior art, allows for consistent delivery of air to wick 118 while heater 120 is powered, which allows for a more consistent cooling of the wick. Furthermore, the more consistent airflow allows for the vapor and droplets caused by the powering of heater 120 to be consistently carried away on the airflow.

FIG. 6 illustrates, through a sectioned view, an alternate embodiment of pod 100. As before, pod 100 is comprised of a reservoir 102 having a post wick air flow passage 104. Reservoir 102 has an open end that is sealed through the insertion of end cap 106 and resilient top cap 122. End cap 106 defines an atomization chamber 116 within which is wick 118 and heater 120. While the embodiment of FIG. 5 illustrates a single pre-wick air flow passage 112, FIG. 6 illustrates an embodiment in which a pair of pre-wick air flow passages 112 a and 112 b provide inlets 114 to direct airflow paths towards wick 118. With this configuration, turbulence is mitigated through the use of pre-wick airflow paths shaped to have curved sidewalls connecting an inlet face having a larger area than the output face of the passage 112 a and 112 b. This provides consistent and predictable airflows toward opposite sides of wick 118 and heater 120. As each airflow passes over wick 118, they are both drawn up towards post-wick airflow passage 104 where they can merge into a single airflow.

Although the illustrations discussed above combine both inlets with smaller output faces than input faces, and a pre wick air flow passage having smaller output faces than input faces, it should be understood that it is possible to implement each of these airflow elements can be implemented separately from the other. A pre-wick airflow passage designed to avoid turbulence in the airflow, can be used in conjunction with cylindrical inlets. Similarly, shaped inlets designed to avoid turbulence can be used with a pre-wick air flow passage that has sharper sides, and may realise many of the benefits of its design with a wider pre-wick airflow passage. In some embodiments, one or both of the air inlet and the pre-wick air flow passage can have sidewalls whose shape is a segment of a common mathematical curve, such as an ellipse, a hyperbola or another known curve.

By creating an airflow path with a more gradual transition between features and/or regions, the airflow passing through the pod is less likely to have zones in which air recirculates where vortices can be created. When vortices are created in a pod with these shaped features and gradual transitions, they are typically less powerful than they would be in a conventional pod because less energy can be transferred from the smooth airflow into them. When a user stops drawing on the vaping device, the driving force behind the airflow stops. Because there are fewer (if any) sharp corners, fewer vortices can develop, and those that do are typically less prominent than they would be if there were sharp corners. It is believed that this is one factor that provides a reduced backflow effect. In situations in which the inlets provide a capillary seal to prevent e-liquid from moving between an atomization chamber and a pre-wick airflow passage, a reduced backflow pressure can be sufficient in preventing e-liquid being drawn through the capillary seal. It should be understood that backflow pressure does not need to be eliminated, it only needs to be mitigated. In some embodiments, the backflow pressure can be reduced to a level that is below the cracking pressure of the capillary seal, thus removing any contribution to leakage from the inlets.

In some embodiments, a pre-wick airflow inlet, such as that illustrated in FIG. 5, may have an inlet face having a diameter of approximately 4 mm, and an output face having a diameter of approximately 2.5 mm. For embodiments such as the dual pre-wick airflow passage of FIG. 6, it should be understood that the sizes of the input and output faces of the passage are constrained by available sizing in associated with the overall design of the pod in question. In some of these embodiments, the inlet may have a height of approximately 3.4 mm, and each of the sidewalls flares out approximately 1 mm from the width of the outlet face. The sizes of the inlets is defined in conjunction with characteristics of the e-liquid so that the outlet face is sufficiently small so as to allow a capillary seal to be formed by the e-liquid. The remaining dimensions, in some embodiments, are similar in ratio to those described above.

Although presented below in the context of use in an electronic nicotine delivery system such as an electronic cigarette (e-cig) or a vaporizer (vape) it should be understood that the scope of protection need not be limited to this space, and instead is delimited by the scope of the claims. Embodiments of the present invention are anticipated to be applicable in areas other than ENDS, including (but not limited to) other vaporizing applications.

In the instant description, and in the accompanying figures, reference to dimensions may be made. These dimensions are provided for the enablement of a single embodiment and should not be considered to be limiting or essential. The sizes and dimensions provided in the drawings are provided for exemplary purposes and should not be considered limiting of the scope of the invention, which is defined solely in the claims. 

1. A pod for storing an atomizable liquid, for use in an electronic vaporizer, the pod comprising: an atomization chamber housing a wick and heater; and a pre-wick airflow passage connected to the atomization chamber by an inlet having an input face larger than an output face and connected by a sidewall.
 2. The pod of claim 1 wherein the atomizable liquid is an e-liquid comprising at least one of propylene glycol, vegetable glycerin, nicotine and a flavoring.
 3. The pod of claim 1 wherein the atomization chamber is further connected to a post wick airflow passage.
 4. The pod of claim 3 having an airflow passage defined by the pre-wick airflow passage, the inlet, the atomization chamber and the post-wick airflow passage connected in series.
 5. The pod of claim 1 wherein the inlet has a sidewall shape defined by a segment of an ellipse.
 6. The pod of claim 1 wherein the output face of the inlet is sized to prevent e-liquid from passing from the output face of the inlet to the input face of the inlet.
 7. The pod of claim 1 wherein the sidewall of the inlet is curved.
 8. The pod of claim 1 wherein the pre-wick airflow passage has an input face and an output face, smaller than the input face, connected by a sidewall.
 9. The pod of claim 8 wherein the pre-wick airflow passage sidewalls has a shape defined by a segment of an ellipse.
 10. The pod of claim 8 further comprising a second pre-wick air flow passage having an input face and an output face connected by a sidewall, where the output face is smaller than the input face and connects the second pre-wick airflow passage to the atomization chamber through an inlet.
 11. The pod of claim 10 wherein the inlet of the second pre-wick air flow passage has an input face larger than an output face connected by a curved sidewall.
 12. The pod of claim 1 wherein the atomization chamber and pre-wick airflow passage are connected by a plurality of inlets.
 13. A pod for storing an atomizable liquid, for use in an electronic vaporizer, the pod comprising: an atomization chamber housing a wick and heater; and a pre-wick airflow passage connected to the atomization chamber by an inlet, the pre-wick airflow passage having an input face larger than an output face of the pre-wick airflow passage and connected by a sidewall.
 14. The pod of claim 13 wherein the atomizable liquid is an e-liquid comprising at least one of propylene glycol, vegetable glycerin, nicotine and a flavoring.
 15. The pod of claim 13 wherein the atomization chamber is further connected to a post wick airflow passage.
 16. The pod of claim 13 wherein the sidewall of the pre-wick airflow passage is curved.
 17. The pod of claim 16 wherein the curve of the pre-wick airflow passage is a segment of an ellipse. 